Documenting basin scale, geometry and provenance through detrital geochemical data: Lessons from the Neoproterozoic to Ordovician Lesser, Greater, and Tethyan Himalayan strata of Bhutan

► Neoproterozoic-Ordovician are key times of deposition along the NE Indian margin. ► Cambro-Ordovician DZ grains in TH and GH rocks suggest retro-arc foreland basin. ► The pre-Himalayan northern Indian margin was complicated but continuous.